For example, patent literature 1 describes a conventional vehicular head-up display device. The vehicular head-up display device (vehicular display device) according to patent literature 1 includes a concave mirror, a motor, and a controller. The concave mirror reflects display light, which comes from a projector, onto a vehicle's windshield. The motor rotates the concave mirror in response to input from a position adjustment switch to change a position of the concave mirror in rotation direction. The controller controls the motor operation.
While using the head-up display, a driver can manipulate the position adjustment switch to adjust the concave mirror to an intended rotation position. The controller operates the motor in response to an input signal from the position adjustment switch to change the concave mirror position in the rotation direction. The controller stores the adjusted concave mirror position as a final rotation stop position. When an ignition switch is turned off, the concave mirror position in the rotation direction is moved to a specified closed position by the controller. When the ignition switch is turned on, the concave mirror position in the rotation direction is returned to the previously adjusted final rotation stop position by the controller.
When the concave mirror is returned from the closed position to the final rotation stop position, the rotation direction to return the concave mirror may coincides with the final rotation direction to adjust the final rotation stop position. In such a case, the motor is supplied with the number of steps Sa to rotate the concave mirror between the closed position and the final rotation stop position to return the concave mirror.
When the concave mirror is returned from the closed position to the final rotation stop position, the rotation direction to return the concave mirror may be opposite to the final rotation direction to adjust the final rotation stop position. In such a case, the motor is supplied with the number of steps Sa supplemented with a specified number of extra steps Sb to rotate the concave mirror between the closed position and the final rotation stop position to return the concave mirror. Accordingly, the concave mirror is once rotated to a position exceeding the final rotation stop position, and the concave mirror is then backward rotated to return to the final rotation stop position.
This can protect the concave mirror against misalignment of the final rotation stop position, without the need for a special mechanism which reduces looseness in a mechanical movable portion or a gear backlash.